/*
 * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */
package jdk.graal.compiler.nodes.virtual;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import jdk.graal.compiler.nodes.java.MonitorIdNode;

/**
 * The class implements a simple linked list of MonitorIdNodes, which can be used to describe the
 * current lock state of an object.
 */
public final class LockState {

    public final MonitorIdNode monitorId;
    public final LockState next;

    public LockState(MonitorIdNode monitorId, LockState next) {
        this.monitorId = monitorId;
        this.next = next;
    }

    @Override
    public String toString() {
        return monitorId.getLockDepth() + (next == null ? "" : "," + next);
    }

    public static List<MonitorIdNode> asList(LockState state) {
        if (state == null) {
            return Collections.emptyList();
        } else {
            ArrayList<MonitorIdNode> result = new ArrayList<>();
            LockState a = state;
            do {
                result.add(a.monitorId);
                a = a.next;
            } while (a != null);
            return result;
        }
    }
}
